1. Field of the Invention
The present invention relates to an apparatus for stirring molten metal by sucking the molten metal into a riser linked to a melting furnace beneath the surface of molten metal in the melting furnace, and returning the molten metal in the riser into the melting furnace.
2. Description of the Prior Art
In one known apparatus, clogging often occurs in the vicinity of the position reached by the surface of molten metal drawn into the riser. That is, air is supplied when the molten metal in the riser is returned to the melting furnace. As a result, the molten metal is oxidized, and the oxides deposit on the wall of riser, or the molten metal in the riser is partly solidified to cause clogging of the riser.
Accordingly, it is an object of the present invention to prevent clogging within the riser and by providing a molten metal agitating apparatus of simple construction.
In other prior art, for example, the upper end of the riser linked to the melting furnace beneath the surface of molten metal in the melting furnace is changed over and connected to a vacuum source or to gas source by way of a changeover valve. As such changeover valve, solenoid valves are widely used, but they are short in service life and often interrupt the continuous operation to melt the metal.
It is another object of the present invention to provide a molten metal stirring apparatus embodying easier maintenance.